Electric-third-rail system



Patented Apr. 25, I899.

L. M. MAXHAM. ELECTRIC THIRD RAIL SYSTEM. (Application filad Apr. 6,1898.) (No Model.) a Sheets-Shet l.

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L. M. MAXHAM.

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No. 623,6!0. Patented Apr. 25, I899. L. M. MAXHAM.

ELECTRIC THIRD RAIL SYSTEM.

(Application m'ed Apr. 6, 1898.)

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LOXVELL MASON MAXHAM, OF BOSTON, MASSACHUSETTS.

ELECTRlC-THlRD-RAIL SYSTEM.

SPECIFICATION forming part of Letters Patent No. 623,610, dated April25, 1899.

Application filed April 6, 1898.

To all whom, it may concern:

Be it known that I, LOWELL MASON MAX- HAM, a citizen of the UnitedStates, residing at Boston, in the county of Suffolk and State ofMassachusetts, have invented a new and useful Electric Third Rail, ofwhich the following is a full, clear, and exact description.

My invention relates to means wherebythe electric current can betransmitted to a car from an electric conductorwhich is normallyinsulated within a third rail; and it comprises, essentially, a hollowthird rail having an electric conductor within it and normally out ofcontact therewith, a movable bar exterior to said third rail, meanswhereby the movement of said bar shall locally complete the circuitbetween said electric conductor and third rail, and a device carried bythe car and adapted to properly operate said bar. Among the deviceswhich Ihave invented for enabling the electric conductor to be put intocontact with the-third rail is a series of rocking arms supported atopposite ends of the electric conductor and movable bar in such.

a manner that the depression of the bar shall automatically elevate anddepress the electric conductor into pressing contact with the ceiling ofthe third rail, and thereby conduct the current to the shoe sliding onthe upper surface of said third rail, which shoe is in electric circuitwith the motor propelling the car. Another device comprises alaterallymovable slide carrying the electric conductor into contact withthe interior of the third rail and adapted to be reciprocated by meansof said movable bar.

Referring to the drawings forming part of this specification, Figure 1is a cross-section of a third rail, the electric conductor locatedtherein, the depressible bar, and the contactshoe and bar-depressingwheel. Fig. 2 is a side view of a section of the third rail and Fig. 3is a plan view of the rocking lever or arm carrying the electricconductor and depressible bar. Fig. 4 is a side elevation of the slidingshoe and the bardepressing wheel carried therewith. Fig. 5 is ahorizontal section of the sliding shoe. Fig. Gisacross-section of thethird rail, showing the manner in which the depressible bar is enabledto move the electric conductor laterally into contact with said rail.Fig. 7 is Serial No. 676,629. (No model.)

a cross-section of the third rail, showing the electric conductor anddepressible bar supported by a rocking arm, but with a spacingrailintroduced between said third rail and movable bar. Fig. 8 is aperspective View of said spacing-rail. Fig. 9 is a perspective view ofthe pivot-spike designed for supporting said rocking arm. Fig. 10is across-section, upon a m uch smallerscale,of the third rail and alliedparts, with the bar-depressing wheel slightly modified.

In all the forms of my invention illustrated, F indicates the thirdrail, A the electric conductor, and E the movable bar. M is the slidingshoe, designed to transmit the current from the third rail through theshoe-carrier N and the spring-supports O to the electric motorpropelling the on r T.

The third rail F is in the form of a hollow arch or inverted trough,either rounded or flat internally, as in Fig. 1 or Fig. 7. Its top isusually fiat in order to better contact with the sliding shoe M. Theelectric conductor A (preferably a heavy copper wire or rod) issupported by one or two wooden strips a, suitably channeled to receiveit, as in Fig. l, or by two wooden strips a ct, adapted to have theconductor clamped between them by the screw or bolt a as in Figs. 6 and7. Referring now to Fig. 1 alone, the said conductor A is shown asresting within the channel of the wooden strip a, which in its turn issupported by the end of the rocking arm 13. Said arm is formed with anotch b, which fits loosely upon the rounded or bluntly-wedged head ofthe pivot-spike O and whose end Z) is engaged by the finger d of thepost D. The lower end d of said'post fits loosely in the hole Z of thesleeper or other foundation-strip L, while its upper end is formed withknees or flanges 01 by which it is screwed to the under side of the barE. The guard-rail K protects the said bar from being struck or depressedby any object narrower than the slot between said guard-rail and thirdrail F.

The wheel P, which is shown in Figs. 1 and t as carried by thesliding-shoedevices, easily enters the slot containing the bar E and bydepressing the latter elevates the electric conduotor A into pressingcontact with the interior surface of the third rail F. As said wheelrolls along the bar E new points of the conductor A are continuallypressed into contact with the third-rail surface above them, while asthe said wheel passes such contacting points return to normal positions.It is designed that the weight of the conductor A, the strip (l, and theenlarged end b of the rocking arms l3 shall more than counterbalance thebar E and the posts I), thereby causing the said conductor to sink toits normal position, as in Fig 7, when the wheel P has passed. Iusually, however, more positively insure such return by providing eachpost D with a spiral spring S, adapted to raise the posts and bar E, asshown in Figs. 1 and 7.

In the modification illustrated in Fig. 7 the main differences over whathas already been described consist in separating the bar E by means ofan insulated spacing-rail G for a suitable distance from the third railin order that the posts D may not have to be oifset, as in Fig. 1, andalso when this third rail is used for street-railways that should ahorses toe-calks enter the slot containing the bar E far enough to raisethe conductor A into contact with the rail F the remainder of the shoeand hoof shall not touch the third rail and the horse be therebyelectrocuted. To retain said spacing-rail in place, the third rail F isformed with an overhanging shoulder f and the rail G with several lugsg, which reach under the ledge 7c of the guard-rail K. A suitableinsulating material 7L is introduced between said spacing and third railof sufficient thickness to thoroughly insulate them when the third railis alive.

Another modification illustrated in Fig. 7 is the substitution of thetwo strips a a for the single one previously described. Said strips areclamped together and to the notched ears b of the rocking arms B bymeans of the screw a and they so clasp the conductor A as to securelyhold it in place. The main purpose for which I design them is to so bindthe conductor between them as to keep it from coiling, kinking, orbending, and thereby bring itself into undesired contact with theinterior of the third rail. To prevent the bar E and the posts D frombeingsurreptitiously removed from their confining-slot,-I form the saidposts with the lug d projecting laterally beneath the ledge 7a of theguard-rail K.

In the modification illustrated in Fig. 6 the clamping-strips a a,holding the electric conductor A, are bolted to the sliding block B, andthe vertical motion of the bar E is made to communicate the desiredhorizontal reciprocation to said block by means of the pivoted elbow Ethe lower end of which engages an eye 13 in said block. A strong spiralspring S elevates the bar E and withdraws the conductor A from contactwith the side of the third rail F. The spacing-rail G is here em-.ployed as in the construction shown in Fi '7 the only difference beingthat here the shelf q is provided for the support of said spring S. Hercalso the opening Z in the sleeper L passes entirely through the same andserves for drainage purposes, it being located directly beneath the slotcontaining the bar E. The other forms of the invention are alsofurnished with similar drainage-openings, but cannot easily be shown onaccount of the post D. It will be noticed that the conductor A is hereshown as hexagonal in cross-section instead of circular, as in the otherfigures. The main object of this is to provide a flat surface forcontacting with the interior of the third rail, and thereby insureincreased surface of electrical contact.

Turning now to Figs. 4 and 5, the construction of the sliding shoe M andits allied parts can be more clearly described. Said shoe is formed withupturned or runner ends, each one-half the width of the shoe. (See m inFig. 5.) The carrierN for the shoe is formed with correspondingly-shapedends n such ends being laterally perforated for the reception of thefastening-boltsa, by which the shoe and its carrier are securedtogether. The carrier N is further formed with the seats, upon which arebolted the lower ends of the S-springs 0, whose upper ends are bolted tothe part T, which may represent the bottom of the car ora beam securedto the car-truck. The object of said springs is to hold the carrier andshoe in the correct position upon the third rail and at the same timepermit the vertical oscillation to which the car-body is liable.Centrally above said carrier N projects a standard N, at whose upper endis an annular enlargement N within which is revolubly held the thiinbleP Revoluble in said sleeve or thiinble P but eccentric with respectthereto, is the shaft P of the depression-wheel P.- The arm 4, formed ofsome non-conducting substance, as Wood, is rigidly connected to saidthimble P by means of the hand r r, bolted thereto, and is oscillatedthrough the agency of the rod R, controlled in any convenient way by themotorman. lVhen said arm is pulled by said rod, the cocentricity of thethimble and shaft causes the wheel P to descend into the slot containingthe bar E; but when the said rod is pushed said wheel is made to riseout from said slotand the third rail made wholly dead. So, also, as thesliding shoe becomes thinner through the elfect of its rubbing contactwith the rail it is not necessary to pull the rod R quite so far inorder to lower the depression-wheel to the point of insuring contactbetween the conductor and third rail.

As shown in Fig. 1, thehand r r is bolted to the thirnble P through theslot 71 in the an- 11 ular head or enlargement N and said hand not onlyserves to turn said thimble P but to retain it in place therein.

In Fig. 10 I show a construction in which the wheel P is held separatelyfrom the shoecarrier N and in which said wheel is prevented frolndescending too deeply into the slot containing the bar E, and therebycause a too-heavy pressure upon the latter by means of the auxiliarywheel Q rotating independently thereof, bntpreferably mounted on thesame axis. This auxiliary wheel rests upon the guard-rail K and sosustains the wheel P at the proper height in the bar-slot. In Fig. 1 Ishow the wheel P itself provided with a flange Q, designed to serve thesame purpose.

It will be noticed that thehollow rail F contains the conductor A at sohigh a pointthat it will be difiicult-for water to reach the latter. Theair in the upper part of the rail tends to prevent the water from risingtherein, and thereby short'circuiting the conductor. To insure'greaterprotection, I insert suitable. elastic material between the ends of therails, asf in Fig. 4, to prevent water and dirt from passing downbetween and entering the conductor-channel. So, also, I pro tect theslot through which the rocking arm enters the conductor-channel bysurrounding said arm with a rubber collar If, as shown in Fig. 7, orother similar material. Although I have shown but a single rocking armand post at any one point, it will be understood that said parts aredesigned to be located at suitable intervals throughout the entirelength of the railway. These arms should be from three to four feetapart, depending upon the stiffness of the electric conductor and itssupporting-strip and also of the bar E, The said bar should be stiffenough and the distance between the postsD short enough to retain theconductor A in contact. with the hollow rail F, even when the wheelP ismidway between the posts. On the other hand, such flexibility anddistance should be sufficient to enable said conductor to sag out ofcontact with the rail F at distances of three or four posts in eitherdirection. In this way not more than one or two rails are kept alive atany one moment. i

The bar E being composed of separate sections touching end to end, thesection immediately beneath the wheel P will be in its depressedcondition, while the one following will be in its normal position. Hencethe said wheel will meet the end of said latter section with apronounced shock. To prevent this, I make the bar E practicallycontinuous by means of strap-pieces e, fastened beneath the adjacentends of the bar-sections by suitable screws 6. Thus arranged thedepression of said bar will be a wave motion, wherein the wheel P willbe at the hollow.

IVhatI claim as my invention, and desire to secure by Letters Patent, isas follows, to wit: 1. In an electric third rail, the combination of anormally-dead rail formed of conduct ing material and made hollowthroughout its length, a naked conductor extending longitudinallythrough said rail, fulcrumed arms supporting said conductor out ofelectric contact with said rail and extending through to the exterior ofthe latter, and means for automatically actuating said arms and movingsaid conductor into contact with said rail.

2. In an electric third rail, the combination of the hollowconducting-rail, the movable electric conductor supported therein andnormally out of contact tl1erewith,the practically continuous flexiblebar located parallel with the said rail, means whereby the depression ofa portion of the said barshall automatically move a correspondingportion of the said electric conductor into electric contact with thesaid rail, and means carried by a car for 10- cally depressing the saidbar and for taking the electric current from the top of the said rail.

3. Inan electric third rail, the combination of the rail, the movableconductor normally out of contact therewith, the depressible bar adaptedto automatically put said conductor and rail in circuit, the slidingshoe adapted to take the current from said rail, and the wheel travelingbeside said shoe and adapted to depress said bar. 4. In an electricthird rail, the combinatio with the hollow rail and the electricconductor located therein, of the bar having means whereby itsdepression shall complete the circuit-between said conductor and hollowrail, the spacing-rail resting beside said hollow rail and having thelateral lug, and the guard-rail having the ledge overhanging said lugand adapted thereby to hold the spacing-rail in 9 position, said lugbeing of sufficient length to give ample room for said bar between saidguard and spacing-rail, substantially as and for the purpose set forth.

5. In an electric third rail, the combination of the hollow rail, theelectric conductor located therein but normally out of contacttherewith, the rocking arm supporting said conductor, the vertical posthaving the finger engagingthe outer end of said arm, the coiled springfor normally elevating said post, and the bar secured to the upper endof said post, substantially as and for the purpose set forth.

(5. In an electric third rail, the combination with the hollow rail andthe electric conductor located therein, of the rocking arm support-- ingsaid conductor, the channeled insulatingstrip located between said armand conductor, and means for depressing the outer end of said arm,substantiallyas and for the purpose set forth.

7. In an electric third rail, the combination of the hollow rail, theelectric conductor normally out of contact therewith, the separableinsulating strips provided with means for clamping them together andadapted to seto partially receive said conductor, the screw adapted toclasp said strips together and fasten them to said ear, and means fordepressing the outer end of said arm, substantially as and for thepurpose set forth.

9. Ihe combination with a normally-dead third rail adapted to be madetemporarily alive by the depression of a bar located at one sidethereof, of the sliding shoe pressing upon said rail, the revolublewheel adapted to depress said bar and carried by said shoe, and meanswhereby said wheel can be raised or lowered at will.

10. In an electric third rail,the combination with the rail, theelectric conductor normally out of contact therewith, and thedepressi'ole bar located to one side of said rail and parallel therewithand adapted when depressed to put said conductor and rail in circuit, ofthe sliding shoe, the post rigidly connected therewith and having theannular head, the eccentric thimble loosely held in said head, the wheelhaving its shaft revoluble in said thimble, and means for partiallyturning said thimble,whereby said wheel can be raised out of contactwith or lowered into a depressive engagement with said bar, for thepurpose set forth.

11. In an electric third rail,the combination with the same, of the shoeslidable thereon, and having the upturned narrowed ends, the carrierhaving corresponding ends, the bolts for fastening said ends together,and an elastic connection between said carrier and the car,substantially as and for the purpose set forth.

12. The combination with the sliding shoe and the carrier holding thesame, of the S- shapcd springs fastened at their endsto said carrier andto any support connected with the car, substantially as and for thepurpose set forth.

13. The combination of the sliding shoe, the carrier having the postformed with the annular head slotted in its upper periphery, theeccentric thimble loosely held therein, the wheel having its shaftrevoluble in said thimble, the hand secured to said t-himble in saidslot, and the insulating-arm held thereby.

14. In an electric third rail,the combination of the electric conductor,the rail normally out of contact therewith, the guard-rail paralleltherewith but at a short distance therefrom, the depressive bar locatedin the slot thus formed and adapted by its depression to complete thecircuit between said conductor and rail, the wheel adapted to enter saidslot and depress said bar and means connected with said wheel andsupported by said guardrail whereby said wheel is prevented fromdepressing said bar below a definite limit, substantially as and for thepurpose set forth.

15. In an electric third rail,the combination of the rail the guard-railparallel therewith, the depressible bar beside said guard-rail adaptedby its depression to put an electric conductor into contact with saidthird rail, the wheel adapted to roll upon said bar and depress it, andthe auxiliary wheel rolling upon said guard-rail and adapted to preventsaid bar from being depressed too far, substantially as and for thepurpose set forth.

In testimony that I claim the foregoing invention I have hereunto set myhand this 22d day of March, 1898.

LOWELL MASON MAXIIAM.

